A previous, commercially sold toner for the IBM 3825 printer is a mixture of several resin components, a charge control agent, and carbon black as a colorant. The 3825 printer employs periodic movement of its photoconductor to replace the previous photoconductor surface as it becomes inoperative from toner filming, periodic replacement of its carrier as the carrier becomes inoperative from toner filming, and periodic replacement of its fuser roller from wear in the region between that occupied by an 11 inch wide paper and remainder of the 14 inch wide fuser roller. Such replacement requirements have not been excessive, and the prior art is not known to teach that they could be further minimized or avoided with a different toner.
It is well recognized in the prior art that use of a gelled (cross-linked) toner does reduce offset of toner to the fuser. U.S. Pat. Nos. 5,334,474 to Abbott et al, 4,556,624 to Gruber et al and Re. 31,072 to Jadwin et al are illustrative. The first patent employs as one resin the same gelled resin as is employed in this invention. The use of a gelled resin just to avoid offset to the fuser roller is often an uneconomic or excessive choice, since the fuser roller can be modified to reject or lose toner in various ways such as by employing a fluorocarbon surface, by oil treatments and by cleaning by mechanical scraping of the fuser roller.
This invention replaces linear resin in a previous toner formula with the same polymer in gelled form. The broad range of benefits obtained by using the gelled resin in accordance with this invention are unexpected and so significant as to warrant use of the gelled resin.